docs: def append_item(self, item):
          """
          Add an item to the end of the menu before the exit item.
  
          Note that Multi-Select Menus will not allow a SubmenuItem to be added, as multi-select menus
          are expected to be used only for executing multiple actions.
  
          Args:
              item (:obj:`MenuItem`): The item to be added
  
          Raises:
              TypeError: If the specified MenuIem is a SubmenuItem.
          """
          if isinstance(item, SubmenuItem):
              raise TypeError("SubmenuItems cannot be added to a MultiSelectMenu")
          super(MultiSelectMenu, self).append_item(item)